Electrified Isoreticular Synthesis of Zeolitic Imidazolate Framework‐90 Membrane Through Self‐Templating for Tunable Gas Separations

Abstract

Abstract Metal–organic frameworks (MOFs) are amenable to isoreticulation, which provides a handle to fine‐tune the pore apertures and thus their gas separation capabilities as molecular‐sieving membranes. Electrified synthesis is an emerging and scalable approach for fabricating MOF membranes, notable for its ultrafast efficiency under ambient conditions. This rapid growth, however, poses a critical challenge to achieving crystallinity during isoreticular synthesis as excessively fast reaction kinetics might lead to the formation of amorphous products lacking long‐range order. Here, we present a self‐templating approach to form in situ structure‐directing subunits, guiding the ordered assembly at extreme kinetics. This strategy enables the electrified isoreticulation of zeolitic imidazolate framework‐8 (ZIF‐8) to ZIF‐90 with slightly larger pore apertures. Compared to the parent ZIF‐8 membrane, which exhibited a propylene permeance of 52 GPU and selectivities of 100–300, the isoreticular ZIF‐90 membrane delivers a ninefold higher permeance of 467 GPU while retaining a robust propylene/propane selectivity of 24.